15. The cell theory was proposed by scientists namely: Matthias Schleiden, Theodore Schwann and Rudolf Virchow to explain how important a cell is. Why is the cell then said to be important to living things? a. I, II and III only 1. The basic unit of structure and organization of organisms is the cell b. I, II and IV only II. The cells just simply make the organisms' body beautiful c. I, III and IV only III. The living things, small or not, are made up of cells d. II, III and IV only IV. The start of all life processes begins with the cel​